Motor driven surgical fastener device with cutting member reversing mechanism

ABSTRACT

A surgical fastener apparatus including a handle, an elongated shaft having a proximal end attached to the handle and a distal end extending therefrom. An end effector comprising a pair of jaws pivoted at a proximal end thereof and movable between an open and closed position, and a cartridge containing a plurality of surgical fasteners, the cartridge attached to the end effector. An electrically powered actuator for deploying the surgical fasteners. An electrically activated reverse mechanism for moving the elongated member from a distal most position within the end effector to a proximal position, the electrically activated reverse mechanism moves the elongated member proximally after the elongated member has moved to the distal most position by moving the trigger to the open position, and wherein after activation of the reverse mechanism proximal movement of the elongated member can be stopped by returning the trigger to its closed position.

CROSS REFERENCE TO RELATED APPLICATIONS

This non-provisional application is a continuation application of U.S.patent application Ser. No. 12/846,249, entitled “Motor Driven SurgicalFastener Device With Cutting Member Reversing Mechanism”, filed on Jul.29, 2010, U.S. Patent Application Publication No. US 2011-0006103 A1which is hereby incorporated by reference in its entirety herein andwhich is a continuation-in-part application of U.S. patent applicationSer. No. 12/693,462, entitled “Driven Surgical Stapler Improvements”, toRyan J. Laurent et al., filed on Jan. 26, 2010, now U.S. Pat. No.8,245,899, which is hereby incorporated by reference in its entiretyherein and which claims the benefit of U.S. Provisional Application Ser.No. 61/150,391 entitled “Motor-Driven Surgical Stapler Improvements” toRyan J. Laurent filed on Feb. 6, 2009, which is hereby incorporated byreference in its entirety herein.

BACKGROUND

An example of a surgical stapler suitable for endoscopic applications isdescribed in U.S. Pat. No. 5,465,895, which is hereby incorporatedherein by reference in its entirety. Such device comprises an endocutterthat has distinct closing and firing actions. Another example of a motordriven surgical stapler is disclosed U.S. Patent Application PublicationNo. US 2007/0175958 A1, entitled “Motor-Driven Surgical Cutting andFastening Instrument With User Feedback System”, published Aug. 2, 2007which is hereby incorporated herein by reference in its entirety.Excerpts of such Publication are presented here to detail its basefunctions, improvements, background, and components. At the end,additional improvements to the system are disclosed.

U.S. Patent Application Publication No. US 2007/0175958 A1 provides inpart that “[a] clinician using this device is able to close the jawmembers upon tissue to position the tissue prior to firing. Once theclinician has determined that the jaw members are properly grippingtissue, the clinician can then fire the surgical stapler with a singlefiring stroke, or multiple firing strokes, depending on the device.Firing the surgical stapler causes severing and stapling the tissue. Thesimultaneous severing and stapling avoids complications that may arisewhen performing such actions sequentially with different surgical toolsthat respectively only sever and staple.”

One specific advantage of being able to close upon tissue before firingis that the clinician is able to verify via an endoscope that thedesired location for the cut has been achieved, including a sufficientamount of tissue has been captured between opposing jaws. Otherwise,opposing jaws may be drawn too close together, especially pinching attheir distal ends, and thus not effectively forming closed staples inthe severed tissue. At the other extreme, an excessive amount of clampedtissue may cause binding and an incomplete firing.

Endoscopic staplers/cutters continue to increase in complexity andfunction with each generation. One of the main reasons for this is thequest for lower force-to-fire (FTF) to a level that all or a greatmajority of surgeons can handle. One known solution to lower FTF is touse C02 or electrical motors. These devices have not faired much betterthan traditional hand-powered devices, but for a different reason.Surgeons typically prefer to experience proportionate force distributionto that being experienced by the end-effector in the forming the stapleto assure them that the cutting/stapling cycle is complete, with theupper limit within the capabilities of most surgeons (usually around15-30 lbs). They also typically want to maintain control of deployingthe staple and being able to stop at anytime if the forces felt in thehandle of the device feel too great or for some other clinical reason.These user-feedback effects are not suitably realizable in presentmotor-driven endocutters. As a result, there is a general lack ofacceptance by physicians of motor-drive endocutters where thecutting/stapling operation is actuated by merely pressing a button.

The foregoing discussion is intended only to illustrate some of theshortcomings present in the field of the invention at the time, andshould not be taken as a disavowal of claim scope.

SUMMARY

In accordance with one general aspect of the present invention, there isprovided a surgical fastener apparatus that includes a handle, anelongated shaft that has a proximal end that is attached to the handleand a distal end that extends therefrom. An end effector is coupled tothe elongated shaft and comprises a pair of jaws that are pivoted at aproximal end thereof and are movable between an open and closedposition. A cartridge that contains a plurality of surgical fasteners isattached to the end effector. The apparatus further includes anelectrically powered actuator for deploying the surgical fasteners. Invarious embodiments, the actuator comprises a power source and a motorand includes an elongated member that extends through the shaft and ismovable distally into the end effector for deploying the staples. Theelongated member may also move proximally back out of the end effector.In certain embodiments, a trigger is attached to the handle and has anopen position and a closed position wherein the trigger activates theactuator. The surgical apparatus further includes an electricallyactivated reverse mechanism for moving the elongated member from adistal most position within the end effector to a proximal position. Theelectrically activated reverse mechanism moves the elongated memberproximally after the elongated member has moved to the distal mostposition by moving the trigger to the open position. After activation ofthe reverse mechanism, proximal movement of the elongated member can bestopped by returning the trigger to its closed position.

In connection with another general aspect of the present invention,there is provided a surgical fastener apparatus that includes a handlethat has an end effector operably coupled thereto. An actuator ismovable within the end effector between an unactuated position toactuated positions within the end effector. An electric motor operablyinterfaces with the actuator to selectively apply a distal drivingmotion thereto to move the actuator from the unactuated position to theactuated positions and to selectively apply a proximal driving motion tothe actuator to retract the actuator to the unactuated position from theactuated positions. In various embodiments, the apparatus furtherincludes a motor control circuit for controlling the motor thatcomprises a power source that is connected to the motor for electricallypowering the motor. The apparatus further includes a current controlcircuit that is connected to the power source for controlling currentsupplied to the motor from the power source. The current control circuitis configured to cause the motor to apply the distal driving motion tothe actuator upon receipt of an actuation motion and also cause themotor to apply the proximal driving motion to the actuator upon receiptof a retraction signal. The current control circuit also is configuredto alter the application of the proximal driving motion upon receipt ofan application of a retraction motion thereto.

In accordance with yet another general aspect of the present invention,there is provided a surgical fastener apparatus that includes a handleand an elongated shaft that has a proximal end attached to the handle. Achannel is coupled to a distal end of the elongated shaft and isconfigured to operably support a surgical staple cartridge therein. Anactuator is movably supported for distal and proximal travel within thechannel. A firing trigger is operably coupled to the handle. Aretraction trigger is operably supported on the firing trigger. Anelectric motor operably interfaces with the actuator to selectivelyapply a distal driving motion thereto to distally move the actuator froman unactuated position to actuated positions and to selectively apply aproximal driving motion to the actuator to retract the actuator to theunactuated position from the actuated positions. The apparatus furtherincludes a motor control circuit for controlling the motor. In variousembodiments, the motor control circuit comprises a power source that isconnected to the motor for electrically powering the motor. The motorcontrol circuit also comprises a current control circuit that isconnected to the power source for controlling current supplied to themotor from the power source. In various embodiments, the current controlcircuit comprises a run motor control switch that is connected to thepower source and is operated by the firing trigger such that uponapplication of the actuation motion to the firing trigger, the run motorcontrol switch permits current to flow to the motor in a first directionto cause the motor to apply the distal driving motion to the actuator.The current control circuit further includes a reverse motor switch thatis connected to the power source such that when the actuator has movedto a distal most actuated position, the reverse motor switch permitscurrent to flow to the motor in a second direction to cause the motor toapply the proximal driving motion to the actuator. A retraction switchis connected to the power source and operated by the refraction triggersuch that upon application of the retraction motion to the retractiontrigger, the retraction switch alters the flow of current in the seconddirection to the motor.

In one general aspect, the present invention is directed to a motorizedsurgical cutting and fastening instrument that provides feedback to theuser regarding the position, force and/or deployment of the endeffector. The instrument, in various embodiments, also allows theoperator to control the end effector, including being able to stopdeployment if so desired. The instrument may include two triggers in itshandle—a closure trigger and a firing trigger—with separate actuationmotions. When an operator of the instrument retracts the closuretrigger, tissue positioned in the end effector may be clamped by the endeffector. Then, when the operator retracts the firing trigger, a motormay power, via a gear drive train, a rotational main drive shaftassembly, which causes a cutting instrument in the end effector to severthe clamped tissue.

In various embodiments, the instrument may comprise a power assistsystem with loading force feedback and control to reduce the firingforce required to be exerted by the operator in order to complete thecutting operation. In such embodiments, the firing trigger may be gearedinto the gear drive train of the main drive shaft assembly. In that way,the operator may experience feedback regarding the force being appliedto the cutting instrument. That is, the loading force on the firingtrigger may be related to the loading force experienced by the cuttinginstrument. Also in such embodiments, because the firing trigger isgeared into the gear drive train, force applied by the operator may beadded to the force applied to the motor.

According to various embodiments, when the firing trigger is retractedan appropriate amount (e.g., five degrees), an on/off switch may beactuated, which sends a signal to the motor to rotate at a specifiedrate, thus commencing actuation of the drive shaft assembly and endeffector. According to other embodiments, a proportional sensor may beused. The proportional sensor may send a signal to the motor to rotateat a rate proportional to the force applied to the firing trigger by theoperator. In that way, the rotational position of the firing trigger isgenerally proportional to where the cutting instrument is in the endeffector (e.g., fully deployed or fully retracted). Further, theoperator could stop retracting the firing trigger at some point in thestroke to stop the motor, and thereby stop the cutting motion. Inaddition, sensors may be used to detect the beginning of the stroke ofthe end effector (e.g., fully retracted position) and the end of thestroke (e.g., fully deployed position), respectively. Consequently, thesensors may provide an adaptive control system for controlling endeffector deployment that is outside of the closed loop system of themotor, gear drive train, and end effector.

In other embodiments, the firing trigger may not be directly geared intothe gear drive train used to actuate the end effector. In suchembodiments, a second motor may be used to apply forces to the firingtrigger to simulate the deployment of the cutting instrument in the endeffector. The second motor may be controlled based on incrementalrotations of the main drive shaft assembly, which may be measured by arotary encoder. In such embodiment, the position of the rotationalposition of the firing trigger may be related to the position of thecutting instrument in the end effector. Additionally, an on/off switchor a proportional switch may be used to control the main motor (i.e.,the motor that powers the main drive shaft).

In various implementations, the end effector may use a helical drivescrew in the base of the end effector to drive the cutting instrument(e.g., knife). Also, the end effector may include a staple cartridge forstapling the severed tissue. According to other embodiments, other meansfor fastening (or sealing) the severed tissue may be used, including RFenergy and adhesives.

Also, the instrument may include a mechanical closure system. Themechanical closure system may include an elongate channel having aclamping member, such as an anvil, pivotably connected to the channel toclamp tissue positioned in the end effector. The user may activate theclamping action of the end effector by retracting the closer trigger,which, through a mechanical closure system, causes the clamping actionof the end effector. Once the clamping member is locked in place, theoperator may activate the cutting operation by retracting the separatefiring trigger. This may cause the cutting instrument to travellongitudinally along the channel in order to cut tissue clamped by theend effector.

In various implementations, the instrument may include a rotational maindrive shaft assembly for actuating the end effector. Further, the maindrive shaft may comprise an articulating joint such that the endeffector may be articulated. The articulation joint may comprise, forexample, a bevel gear assembly, a universal joint, or a flexible torsioncable capable of transmitting torsion force to the end effector.

Other aspects of the present invention are directed to variousmechanisms for locking the closure trigger to a lower, pistol-gripportion of the handle. Such embodiments free up space in the handledirectly above and behind the triggers for other components of theinstrument, including components of the gear drive train and themechanical closure system.”

The disclosure herein shows how one could embody a battery powered geardriven self-contained endoscopic stapling device.

BRIEF DESCRIPTION OF DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention itself will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIGS. 1 and 2 are perspective views of a surgical cutting and fasteninginstrument according to various embodiments of the present invention;

FIGS. 3-5 are exploded views of an end effector and shaft of theinstrument according to various embodiments of the present invention;

FIG. 6 is a side view of the end effector according to variousembodiments of the present invention;

FIG. 7 is an exploded view of the handle of the instrument according tovarious embodiments of the present invention;

FIGS. 8 and 9 are partial perspective views of the handle according tovarious embodiments of the present invention;

FIG. 10 is a side view of the handle according to various embodiments ofthe present invention;

FIGS. 10A-10B illustrate a proportional sensor or switch that may beused according to various embodiments of the present invention;

FIG. 11 is a schematic diagram of a current control circuit used in theinstrument according to various embodiments of the present invention;

FIG. 12 is a side view of another handle according to variousembodiments of the present invention;

FIG. 13 is a schematic diagram of another current control circuit usedin the instrument according to various embodiments of the presentinvention;

FIG. 14 is a schematic diagram of another current control circuit usedin the instrument according to various embodiments of the presentinvention;

FIG. 15 is a schematic diagram of another circuit used in the instrumentaccording to various embodiments of the present invention;

FIG. 15A is a schematic diagram of another current control circuit usedin the instrument according to various embodiments of the presentinvention;

FIG. 15B is a schematic diagram of another current control circuit usedin the instrument according to various embodiments of the presentinvention;

FIGS. 16-17 illustrate different mechanisms for locking the closuretrigger according to various embodiments of the present invention;

FIG. 18 is a schematic diagram of another current control circuit usedin the instrument according to various embodiments of the presentinvention;

FIG. 19 is a cross-sectional view of an end effector embodiment of thepresent invention;

FIG. 20 is a side elevational view of a knife assembly or actuatorembodiment of the present invention;

FIG. 21 is a side elevational view of another knife assembly or actuatorembodiment of the present invention;

FIG. 22 is a side elevational view of another knife assembly or actuatorembodiment of the present invention;

FIG. 23 is a perspective view of a distal end of surgical stapler inaccordance with an embodiment of the present invention;

FIG. 24 is a perspective view of a distal end of surgical stapler inaccordance with an embodiment of the present invention with thecartridge removed from the channel;

FIG. 25 is a view of a distal end of surgical stapler in accordance withan embodiment of the present invention similar to FIG. 1 showing alockout indicator; and

FIG. 26 is a perspective view of a proximal end of surgical stapler inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The owner of the subject application also owns the following U.S. patentapplications that were filed on even date herewith and which are eachherein incorporated by reference in their respective entirety:

U.S. patent application Ser. No. 12/846,228, entitled “Motor DrivenSurgical Fastener Device With Cutting Member Lockout Arrangements”, nowU.S. Patent Publication No. 2011/0006101; and

U.S. patent application Ser. No. 12/846,237, entitled “Motor DrivenSurgical Fastener Device With Mechanisms For Adjusting a Tissue GapWithin the End Effector”, now U.S. Patent Publication No. 2011/0011915.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those of ordinary skill in the art will understand that thedevices and methods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the various embodiments of the present invention is definedsolely by the claims. The features illustrated or described inconnection with one exemplary embodiment may be combined with thefeatures of other embodiments. Such modifications and variations areintended to be included within the scope of the present invention.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” or “an embodiment”, “an implementation”or “various implementations” or the like, means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment. Thus, appearances ofthe phrases “in various embodiments,” “in some embodiments,” “in oneembodiment”, or “in an embodiment”, “an implementation” or “variousimplementations” or the like, in places throughout the specification arenot necessarily all referring to the same embodiment or implementation.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments orimplementations. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation. Such modifications and variations are intended to beincluded within the scope of the present invention.

The terms “proximal” and “distal” are used herein with reference to aclinician manipulating the handle portion of the surgical instrument.The term “proximal” referring to the portion closest to the clinicianand the term “distal” referring to the portion located away from theclinician. It will be further appreciated that, for convenience andclarity, spatial terms such as “vertical”, “horizontal”, “up”, and“down” may be used herein with respect to the drawings. However,surgical instruments are used in many orientations and positions, andthese terms are not intended to be limiting and/or absolute.

FIGS. 1 and 2 depict a surgical cutting and fastening instrument 10according to various embodiments of the present invention. Theillustrated embodiment is an endoscopic surgical instrument 10 and ingeneral, the embodiments of the instrument 10 described herein areendoscopic surgical cutting and fastening instruments. It should benoted, however, that according to other embodiments of the presentinvention, the instrument 10 may be a non-endoscopic surgical cuttinginstrument, such as a laproscopic instrument.

The surgical instrument 10 depicted in FIGS. 1 and 2 comprises a handle6, a shaft 8, and an articulating end effector 12 pivotally connected tothe shaft 8 at an articulation pivot 14. An articulation control 16 maybe provided adjacent to the handle 6 to effect rotation of the endeffector 12 about the articulation pivot 14. It will be appreciated thatvarious embodiments may include a non-pivoting end effector, andtherefore may not have an articulation pivot 14 or articulation control16. Also, in the illustrated embodiment, the end effector 12 isconfigured to act as an endocutter for clamping, severing and staplingtissue, although, in other embodiments, different types of end effectorsmay be used, such as end effectors for other types of surgical devices,such as graspers, cutters, staplers, clip appliers, access devices,drug/gene therapy devices, ultrasound, RF or laser devices, etc.

The handle 6 of the instrument 10 may include a closure trigger 18 and afiring trigger 20 for actuating the end effector 12. It will beappreciated that instruments having end effectors directed to differentsurgical tasks may have different numbers or types of triggers or othersuitable controls for operating the end effector 12. The end effector 12is shown separated from the handle 6 by a preferably elongate shaft 8.In one embodiment, a clinician or operator of the instrument 10 mayarticulate the end effector 12 relative to the shaft 8 by utilizing thearticulation control 16, as described in more detail in U.S. Pat. No.7,670,334, entitled “Surgical Instrument Having An Articulating EndEffector,” by Geoffrey C. Hueil et al., which is incorporated herein byreference in its entirety.

The end effector 12 includes in this example, among other things, anelongated channel 22 configured to operably support a staple cartridge34 therein and a pivotally translatable clamping member, such as ananvil 24, which are maintained at a spacing that assures effectivestapling and severing of tissue clamped in the end effector 12. Thehandle 6 includes a pistol grip 26 toward which a closure trigger 18 ispivotally drawn by the clinician to cause clamping or closing of theanvil 24 towards the elongated channel 22 of the end effector 12 tothereby clamp tissue positioned between the anvil 24 and elongatedchannel 22. The firing trigger 20 is farther outboard of the closuretrigger 18. Once the closure trigger 18 is locked in the closureposition as further described below, the firing trigger 20 may rotateslightly toward the pistol grip 26 so that it can be reached by theoperator using one hand. Then the operator may pivotally draw the firingtrigger 20 toward the pistol grip 26 to cause the stapling and severingof clamped tissue in the end effector 12. In other embodiments,different types of clamping members besides the anvil 24 could be used,such as, for example, an opposing jaw, etc.

The closure trigger 18 may be actuated first. Once the clinician issatisfied with the positioning of the end effector 12, the clinician maydraw back the closure trigger 18 to its fully closed, locked positionproximate to the pistol grip 26. The firing trigger 20 may then beactuated. The firing trigger 20 returns to the open position (shown inFIGS. 1 and 2) when the clinician removes pressure, as described morefully below. A release button on the handle 6, when depressed mayrelease the locked closure trigger 18. The release button may beimplemented in various forms such as, for example, slide release button160 shown in FIG. 16, and/or button 172 shown in FIG. 17.

FIGS. 3-6 show embodiments of a rotary-driven end effector 12 and shaft8 according to various embodiments. FIG. 3 is an exploded view of theend effector 12 according to various embodiments. As shown in theillustrated embodiment, the end effector 12 may include, in addition tothe previously-mentioned channel 22 and anvil 24, a cutting instrument32, a sled 33, a staple cartridge 34 that is removably seated in thechannel 22, and a helical screw shaft 36. The cutting instrument 32 maybe, for example, a knife As used herein with respect to at least oneembodiment, the term “actuator” may refer to the knife and/or sled. Theanvil 24 may be pivotably opened and closed at pivot pins 25 connectedto the proximate end of the channel 22. The anvil 24 may also include atab 27 at its proximate end that is inserted into a component of themechanical closure system (described further below) to open and closethe anvil 24. When the closure trigger 18 is actuated, that is, drawn inby a user of the instrument 10, the anvil 24 may pivot about the pivotpins 25 into the clamped or closed position. If clamping of the endeffector 12 is satisfactory, the operator may actuate the firing trigger20, which, as explained in more detail below, causes the knife 32 andsled 33 to travel longitudinally along the channel 22, thereby cuttingtissue clamped within the end effector 12. The movement of the sled 33along the channel 22 causes the staples (not shown) of the staplecartridge 34 to be driven through the severed tissue and against theclosed anvil 24, which turns the staples to fasten the severed tissue.In various embodiments, the sled 33 may be an integral component of thecartridge 34. U.S. Pat. No. 6,978,921, entitled “Surgical StaplingInstrument Incorporating an E-beam Firing Mechanism” to Shelton, IV etal., which is incorporated herein by reference, provides more detailsabout such two-stroke cutting and fastening instruments. The sled 33 maybe part of the cartridge 34, such that when the knife 32 retractsfollowing the cutting operation, the sled 33 does not retract.

FIGS. 4 and 5 are exploded views and FIG. 6 is a side view of the endeffector 12 and shaft 8 according to various embodiments. As shown inthe illustrated embodiment, the shaft 8 may include a proximate closuretube 40 and a distal closure tube 42 pivotably linked by a pivot link44. The distal closure tube 42 includes an opening 45 into which the tab27 on the anvil 24 is inserted in order to open and close the anvil 24,as further described below. Disposed inside the closure tubes 40, 42 maybe a proximate spine tube 46. Disposed inside the proximate spine tube46 may be a main rotational (or proximate) drive shaft 48 thatcommunicates with a secondary (or distal) drive shaft 50 via a bevelgear assembly 52. The secondary drive shaft 50 is connected to a drivegear 54 that engages a proximate drive gear 56 of the helical screwshaft 36. The vertical bevel gear 52 b may sit and pivot in an opening57 in the distal end of the proximate spine tube 46. A distal spine tube58 may be used to enclose the secondary drive shaft 50 and the drivegears 54, 56. Collectively, the main drive shaft 48, the secondary driveshaft 50, and the articulation assembly (e.g., the bevel gear assembly52 a-c) are sometimes referred to herein as the “main drive shaftassembly.”

A bearing 38, positioned at a distal end of the staple channel 22,receives the helical drive screw 36, allowing the helical drive screw 36to freely rotate with respect to the channel 22. The helical screw shaft36 may interface a threaded opening (not shown) of the knife 32 suchthat rotation of the shaft 36 causes the knife 32 to translate distallyor proximately (depending on the direction of the rotation) through thestaple channel 22. Accordingly, when the main drive shaft 48 is causedto rotate upon application of an actuation motion to the firing trigger20 (as explained in more detail below), the bevel gear assembly 52 a-ccauses the secondary drive shaft 50 to rotate, which in turn, because ofthe engagement of the drive gears 54, 56, causes the helical screw shaft36 to rotate, which causes the knife driving member 32 to travellongitudinally along the channel 22 to cut any tissue clamped within theend effector 12. The sled 33 may be made of, for example, plastic, andmay have a sloped distal surface. As the sled 33 traverses the channel22, the sloped forward surface may push up or drive the staples in thestaple cartridge through the clamped tissue and against the anvil 24.The anvil 24 forms or turns the staples, thereby stapling the severedtissue. When the knife 32 is retracted, the knife 32 and sled 33 maybecome disengaged, thereby leaving the sled 33 at the distal end of thechannel 22.

FIGS. 7-10 illustrate an exemplary embodiment of a motor-drivenendocutter, and in particular the handle thereof, that providesuser-feedback regarding the deployment and loading force of the cuttinginstrument 32 in the end effector 12. In addition, the embodiment mayuse power provided by the user in retracting the firing trigger 20 topower the device (a so-called “power assist” mode). The embodiment maybe used with the rotary driven end effector 12 and shaft 8 embodimentsdescribed above. As shown in the illustrated embodiment, the handle 6includes exterior lower side pieces 59, 60 and exterior upper sidepieces 61, 62 that fit together to form, in general, the exterior of thehandle 6. In various embodiments, the rotary driven end effector may bepowered by a motor 65 that is disposed in an upper portion of the pistolgrip portion 26 of the handle and powered by a power source 64. Thepower source 64 may comprise a battery or a supply of alternatingcurrent. In a preferred embodiment, the power source 64 comprises a Liion battery that is supported in the pistol grip portion 26 of thehandle 6. According to various embodiments, the motor 65 may be a DCbrushed driving motor having a maximum rotation of, approximately, 5000RPM. The motor 65 may drive a 90 degree bevel gear assembly 66comprising a first bevel gear 68 and a second bevel gear 70. The bevelgear assembly 66 may drive a planetary gear assembly 72. The planetarygear assembly 72 may include a pinion gear 74 connected to a drive shaft76. The pinion gear 74 may drive a mating ring gear 78 that drives ahelical gear drum 80 via a drive shaft 82. A ring 84 may be threaded onthe helical gear drum 80. Thus, when the motor 65 rotates, the ring 84is caused to travel along the helical gear drum 80 by means of theinterposed bevel gear assembly 66, planetary gear assembly 72 and ringgear 78.

The handle 6 may also include a run motor switch 110 (see FIG. 10) incommunication with the firing trigger 20 to receive an actuation motionfrom the firing trigger 20 when the firing trigger has been drawn in (or“closed”) toward the pistol grip portion 26 of the handle 6 by theoperator to thereby actuate the cutting/stapling operation by the endeffector 12. The run motor switch 110 may be a proportional sensor suchas, for example, a rheostat or variable resistor. When the firingtrigger 20 is drawn in, the run motor switch 110 permits current to flowfrom the power source 64 to the motor 65. When the run motor switch 110is a variable resistor or the like, the rotation of the motor 65 may begenerally proportional to the amount of movement of the firing trigger20. That is, if the operator only draws or closes the firing trigger 20in a small amount, the rotation of the motor 65 is relatively low. Whenthe firing trigger 20 is fully drawn in (or in the fully closedposition), the rotation of the motor 65 is at its maximum. In otherwords, the harder the user pulls on the firing trigger 20, the morevoltage is applied to the motor 65, causing greater rates of rotation.

The handle 6 may include a middle handle piece 104 adjacent to the upperportion of the firing trigger 20. The handle 6 may also include a biasspring 112 that is connected between posts on the middle handle piece104 and the firing trigger 20. The bias spring 112 may bias the firingtrigger 20 to its fully open position. In that way, when the operatorreleases the firing trigger 20, the bias spring 112 will pull the firingtrigger 20 to its open position, thereby deactivating the run motorswitch 110 to stop rotation of the motor 65. Moreover, by virtue of thebias spring 112, any time a user closes the firing trigger 20, the userwill experience resistance to the closing operation, thereby providingthe user with feedback as to the amount of rotation exerted by the motor65. Further, the operator could stop retracting the firing trigger 20 tothereby deactivate the run motor switch 110 and stop the motor 65. Assuch, the user may stop the deployment of the end effector 12, therebyproviding a measure of control of the cutting/fastening operation to theoperator.

The distal end of the helical gear drum 80 includes a distal drive shaft120 that drives a ring gear 122, which mates with a pinion gear 124. Thepinion gear 124 is connected to the main drive shaft 48 of the maindrive shaft assembly. In that way, rotation of the motor 65 causes themain drive shaft assembly to rotate, which causes actuation of the endeffector 12, as described above.

The ring 84 threaded on the helical gear drum 80 may include a post 86that is disposed within a slot 88 of a slotted arm 90. The slotted arm90 has an opening 92 its opposite end 94 that receives a pivot pin 96that is connected between the handle exterior side pieces 59, 60. Thepivot pin 96 is also disposed through an opening 100 in the firingtrigger 20 and an opening 102 in the middle handle piece 104.

In addition, the handle 6 may include a reverse motor switch (orend-of-stroke switch) 130 and a stop motor (or beginning-of-stroke)switch 142. In various embodiments, the reverse motor switch 130 may bea limit switch located at the distal end of the helical gear drum 80such that the ring 84 threaded on the helical gear drum 80 contacts andtrips the reverse motor switch 130 when the ring 84 reaches the distalend of the helical gear drum 80. The reverse motor switch 130, whenactivated, sends a signal (i.e., permits current to flow) to the motor65 to reverse its rotation direction, thereby withdrawing the knife 32of the end effector 12 following the cutting operation.

The stop motor switch 142 may be, for example, a normally-closed limitswitch. In various embodiments, it may be located at the proximate endof the helical gear drum 80 so that the ring 84 trips the switch 142when the ring 84 reaches the proximate end of the helical gear drum 80.

In operation, when an operator of the instrument 10 applies an actuationmotion to the firing trigger 20, the run motor switch 110 detects thedeployment of the firing trigger 20 and sends a signal (i.e., permitscurrent to flow) to the motor 65 to cause forward rotation of the motor65, for example, at a rate proportional to how hard the operator pullsback the firing trigger 20. The forward rotation of the motor 65 in turncauses the ring gear 78 at the distal end of the planetary gear assembly72 to rotate, thereby causing the helical gear drum 80 to rotate,causing the ring 84 threaded on the helical gear drum 80 to traveldistally along the helical gear drum 80. The rotation of the helicalgear drum 80 also drives the main drive shaft assembly as describedabove, which in turn causes deployment of the knife 32 in the endeffector 12. That is, the knife 32 and sled 33 are caused to distallytraverse the channel 22 longitudinally, thereby cutting tissue clampedin the end effector 12. Also, the stapling operation of the end effector12 is caused to happen in embodiments where a stapling-type end effector12 is used.

By the time the cutting/stapling operation of the end effector 12 iscomplete, the ring 84 on the helical gear drum 80 will have reached thedistal end of the helical gear drum 80, thereby causing the reversemotor switch 130 to be activated, which sends a signal (i.e., permitscurrent to flow) to the motor 65 to cause the motor 65 to reverse itsrotation. This in turn causes the knife 32 to retract, and also causesthe ring 84 on the helical gear drum 80 to move back to the proximateend of the helical gear drum 80.

The middle handle piece 104 includes a backside shoulder 106 thatengages the slotted arm 90 as best shown in FIGS. 8 and 9. The middlehandle piece 104 also has a forward motion stop 107 that engages thefiring trigger 20. The movement of the slotted arm 90 is controlled, asexplained above, by rotation of the motor 65. When the slotted arm 90rotates counter clockwise as the ring 84 travels from the proximate endof the helical gear drum 80 to the distal end, the middle handle piece104 will be free to rotate counter clockwise. Thus, as the user draws inthe firing trigger 20, the firing trigger 20 will engage the forwardmotion stop 107 of the middle handle piece 104, causing the middlehandle piece 104 to rotate counter clockwise. Due to the backsideshoulder 106 engaging the slotted arm 90, however, the middle handlepiece 104 will only be able to rotate counter clockwise as far as theslotted arm 90 permits. In that way, if the motor 65 should stoprotating for some reason, the slotted arm 90 will stop rotating, and theuser will not be able to further draw in the firing trigger 20 becausethe middle handle piece 104 will not be free to rotate counter clockwisedue to the slotted arm 90.

FIGS. 10A and 10B illustrate two states of a variable switches orsensors that may be used as the run motor switch 110 according tovarious embodiments of the present invention. The run motor switch 110may include a face portion 280, a first electrode (A) 282, a secondelectrode (B) 284, and a compressible dielectric material 286 betweenthe electrodes 282, 284, such as, for example, an electroactive polymer(EAP). The run motor switch 110 may be positioned such that the faceportion 280 contacts the firing trigger 20 when retracted. Accordingly,when the firing trigger 20 is retracted, the dielectric material 286 iscompressed, as shown in FIG. 10B, such that the electrodes 282, 284 arecloser together. Since the distance “b” between the electrodes 282, 284is directly related to the impedance between the electrodes 282, 284,the greater the distance the more impedance, and the closer the distancethe less impedance. In that way, the amount that the dielectric 286 iscompressed due to retraction of the firing trigger 20 (denoted as force“F” in FIG. 10B) is proportional to the impedance between the electrodes282, 284, which can be used to proportionally control the motor 65.

Components of an exemplary closure system for closing (or clamping) theanvil 24 of the end effector 12 by retracting the closure trigger 18 arealso shown in FIGS. 7-10. In the illustrated embodiment, the closuresystem includes a yoke 250 connected to the closure trigger 18 by apivot pin 251 inserted through aligned openings in both the closuretrigger 18 and the yoke 250. A pivot pin 252, about which the closuretrigger 18 pivots, is inserted through another opening in the closuretrigger 18 which is offset from where the pin 251 is inserted throughthe closure trigger 18. Thus, retraction of the closure trigger 18causes the upper part of the closure trigger 18, to which the yoke 250is attached via the pin 251, to rotate counterclockwise. The distal endof the yoke 250 is connected, via a pin 254, to a first closure bracket256. The first closure bracket 256 connects to a second closure bracket258. Collectively, the closure brackets 256, 258 define an opening inwhich the proximate end of the proximate closure tube 40 (see FIG. 4) isseated and held such that longitudinal movement of the closure brackets256, 258 causes longitudinal motion by the proximate closure tube 40.The instrument 10 also includes a closure rod 260 disposed inside theproximate closure tube 40. The closure rod 260 may include a window 261into which a post 263 on one of the handle exterior pieces, such asexterior lower side piece 59 in the illustrated embodiment, is disposedto fixedly connect the closure rod 260 to the handle 6. In that way, theproximate closure tube 40 is capable of moving longitudinally relativeto the closure rod 260. The closure rod 260 may also include a distalcollar 267 that fits into a cavity 269 in proximate spine tube 46 and isretained therein by a cap 271 (see FIG. 4).

In operation, when the yoke 250 rotates due to retraction of the closuretrigger 18, the closure brackets 256, 258 cause the proximate closuretube 40 to move distally (i.e., away from the handle end of theinstrument 10), which causes the distal closure tube 42 to movedistally, which causes the anvil 24 to rotate about the pivot pins 25into the clamped or closed position. When the closure trigger 18 isunlocked from the locked position, the proximate closure tube 40 iscaused to slide proximately, which causes the distal closure tube 42 toslide proximately, which, by virtue of the tab 27 being inserted in thewindow 45 of the distal closure tube 42, causes the anvil 24 to pivotabout the pivot pins 25 into the open or unclamped position. In thatway, by retracting and locking the closure trigger 18, an operator mayclamp tissue between the anvil 24 and channel 22, and may unclamp thetissue following the cutting/stapling operation by unlocking the closuretrigger 20 from the locked position.

FIG. 11 is a schematic diagram of a current control circuit of theinstrument 10 according to various embodiments of the present invention.When an operator initially pulls in the firing trigger 20 after lockingthe closure trigger 18, the run motor switch 110 is activated, allowingcurrent to flow therethrough. If the normally-open reverse motor sensorswitch 130 is open (meaning the end of the end effector stroke has notbeen reached), current will flow to a single pole, double throw relay132. Since the reverse motor sensor switch 130 is not closed, theinductor 134 of the relay 132 will not be energized, so the relay 132will be in its non-energized state. The circuit also includes acartridge lockout switch 136. If the end effector 12 includes a staplecartridge 34, the switch 136 will be in the closed state, allowingcurrent to flow. Otherwise, if the end effector 12 does not include astaple cartridge 34, the switch 136 will be open, thereby preventing thebattery 64 from powering the motor 65.

When the staple cartridge 34 is present, the switch 136 is closed, whichenergizes a single pole, single throw relay 138. When the relay 138 isenergized, current flows through the relay 136, through the variableresistor (run motor) switch 110, and to the motor 65 via a double pole,double throw relay 140, thereby powering the motor 65 and allowing it torotate in the forward direction.

When the end effector 12 reaches the end of its stroke, the reversemotor switch 130 will be activated, thereby closing the reverse motorswitch 130 and energizing the relay 134. This causes the relay 134 toassume its energized state, which causes current to bypass the cartridgelockout switch 136 and variable resistor 110, and instead causes currentto flow to both the normally-closed double pole, double throw relay 142and back to the motor 65, but in a manner, via the relay 140, thatcauses the motor 65 to reverse its rotational direction.

Because the stop motor switch 142 is normally-closed, current will flowback to the relay 134 to keep it closed until the stop motor switch 142opens. When the knife 32 is fully retracted, the stop motor switch 142is activated, causing the stop motor switch 142 to open, therebyremoving power from the motor 65.

In other embodiments, rather than a proportional-type switch 110, anon-off type sensor or switch could be used. In such embodiments, therate of rotation of the motor 65 would not be proportional to the forceapplied by the operator. Rather, the motor 65 would generally rotate ata constant rate. But the operator would still experience force feedbackbecause the firing trigger 20 is geared into the gear drive train.

As indicated above, there are several steps within the function of astapler that generally must be accomplished in an established order. Forexample, once the closure trigger is clamped, the firing cycle may beactuated. After the knife has been fully deployed, then refraction ofthe system is the next sequential step. With the inclusion of a powersource other than the user (i.e. batteries or pneumatics) the ability toreduce user initiated steps (and therefore device complexity) the systemitself, as was discussed above, can begin to accomplish these stepsitself.

It may be desirable, however, for the user to intuitively be able todelay, slow or stop these otherwise “automatic” actuations. For example,the same actuation button that would allow for firing initiation in atactile feedback device like the devices disclosed in U.S. patentapplication Ser. No. 11/344,035, now U.S. Pat. No. 7,422,139, thedisclosure of which is herein incorporated by reference in its entiretycould be used to slow or stop an automatic return system by the userdepressing the button during the retraction.

For example, FIGS. 12 and 13 illustrate another embodiment of thepresent invention wherein a retraction trigger 121 is supported on thefiring trigger 20 for travel therewith. More specifically, theretraction trigger 121 is pivotally supported on firing trigger pin 96and protrudes through a slot (not shown) in the firing trigger 20. Aspring 125 is attached between a coupling portion 123 of the firingtrigger 100 and a mounting portion 127 of the retraction trigger 121 tobias the retraction trigger 121 into an unactuated position. A second,normally-closed, refraction switch 131 is mounted within the handle andis oriented such that, as the firing trigger 20 is moved between a fullyactuated position to a fully unactuated position, an activation portion129 of the retraction trigger 121 does not activate the retractionswitch 131. However, the mounting portion 127 and activation portion 129of the retraction trigger 121 are so configured such that the activationportion 129 may be brought into activation contact with the retractionswitch 131 by depressing the retraction trigger 121 towards the firingtrigger 20 regardless of where the firing trigger 20 is located duringthe retraction process.

As was discussed above, when the end effector 12 reaches the end of itsstroke, the end of stroke switch 130 will be activated. As shown in theexample of FIG. 13, the retraction switch 131 is in series with theend-of-stroke switch 130. Because the retraction switch 131 is normallyclosed, relay 134 will be energized when both switches 130, 131 areclosed. This causes the relay 134 to assume its energized state, whichcauses current to bypass the cartridge lockout sensor 136 and variableresistor 110. Current to flows to the double pole, double throw relay140 and to the motor 65, but in a manner, via the relay 140, that causesthe motor 65 to reverse its rotational direction. Because thebeginning-of-stroke switch 142 is closed, current will flow back to therelay 134 to keep it closed until the switch 142 opens. When the knife32 is fully retracted, the beginning-of-stroke switch 142 is opened,thereby removing power from the motor 65. If, however, the user wants toslow down the retraction process, the user may depress the retractiontrigger 121 to activate the variable resistance portion 133 of theretraction switch 131. When the retraction trigger 121 is not depressed,the resistance of the variable resistance portion 133 is a minimum. Whenthe trigger 121 is depressed, the resistance of the variable resistanceportion 133 increases in proportion to the depressing force of theretraction trigger 121 to reduce the current to the motor 65. Furtherdepression of the retraction trigger 121 will slow the retractionprocess until the normally closed contact 135 portion of the retractionswitch 131 opens and stops the current flow to the motor 65. In variousembodiments, once the user releases the retraction trigger 121, thespring 125 will move the retraction trigger 121 to an unactuatedposition and the contact portion 135 of switch 131 will return to thenormally closed position and thereby permit current to flow again to themotor 65 to complete the retraction process.

The unique and novel features of the retraction switch and retractiontrigger arrangements described above may also be employed in connectionwith the various embodiments disclosed in U.S. Patent ApplicationPublication No. US 2010/007674 A1, and U.S. Pat. No. 7,422,139 whichhave both been herein incorporated by reference in their respectiveentireties. For example, FIG. 14 shows another embodiment of a currentcontrol circuit embodiment of the present invention. When (i) the runmotor (or fire) switch 110 is closed (it is shown in an open state inFIG. 14), (ii) the safety switch 240 is closed (it is shown open in FIG.14) indicating that the device safety is set, and (iii) thenormally-closed lockout switch 242 is opened indicating that theinstrument is not in a lock-out condition, current flows through thesafety switch 240, through the lockout indicator 244 (which may be a LEDas shown in FIG. 14) to the motor 65. When the end of the cutting strokeis reached, the end-of-stroke or direction switch 130 is switched,reversing the direction of the motor 65 (with the fire switch 110 alsohaving been released). In this state, current also flows through areverse direction indicator 246, such as an LED, providing a visualindication that the motor direction has been reversed.

As shown in FIG. 14, the circuit may also comprise a manual returnswitch 248. The operator may manually actuate this switch if the cuttinginstrument 32 has only been partially fired. Switching the manual returnswitch 248 causes the motor 65 to reverse rotate, causing the cuttinginstrument 32 to return to its original or home position. If, the userdesires to slow down or stop the retraction process, the user depressesthe retraction trigger 121 to activate the variable resistance portion133 of the retraction switch 131. When the trigger 121 is depressed, theresistance increases in portion to the depressing force to reduce thecurrent to the motor 65. Further depression of the retraction trigger121 will slow the retraction process until the normally closed contact135 portion of the retraction switch 131 opens and stops the currentflow to the motor 65. In various embodiments, once the user releases theretraction trigger 121, the spring 125 will move the retraction trigger121 to an unactuated position and the contact portion 135 of switch 131will return to the normally closed position and thereby permit currentto flow again to the motor 65 to complete the retraction process.

Additional configurations for motorized surgical instruments aredisclosed in published U.S. Patent Application Publication No. US2010/0076474 A1, entitled “Motor-Driven Surgical Cutting Instrument,”which is incorporated herein by reference in its entirety. For example,FIG. 15 is a schematic diagram of another current control circuitaccording to various embodiments of the present invention. In variousembodiments, the motor control circuit may include one of moreintegrated circuits (ICs), such as, for example, a processor, memory,microcontroller, time circuits, etc. In other embodiments, the motorcontrol circuit may not comprise any ICs. Such a non-IC current controlcircuit may be advantageous because it is often difficult, complicated,and expensive to sterilize a surgical instrument including ICs.

When an operator initially applies an actuation motion to the firingtrigger 20 after locking the closure trigger 18, the run motor switch110 is activated (or closed), allowing current to flow therethrough. Ifthe normally open reverse motor sensor switch 130 is open (meaning theend of the end effector stroke has not been reached), current will flowto a single pole, double throw relay 132. When the reverse motor sensorswitch 130 is not closed, a coil 134 of the relay 132 will not beenergized, so the relay 132 will be in its de-energized state.

As shown in FIG. 15, the circuit may also include a resistive element144 and a switch 146 connected in parallel, with the paralleled elementsconnected in series with the relay 132. The resistive element 144 andthe switch 146 are also connected to the power source 64. The switch 146may be controlled by a control circuit 148 that is responsive to thecutting instrument position sensor 150. According to variousembodiments, the control circuit 148 may open the switch 146 when thecutting instrument 32 is (i) very near to the beginning of its strokeand (ii) very near to the end of its stroke. For example, the controlcircuit may open the switch when the cutting instrument 32 is (i) 0.001inches from the beginning point of its stroke and (ii) 0.001 inches fromthe end of its stroke, as determined by the cutting instrument positionsensor 150. With the switch 146 open, current flows through theresistive element 144, and then through the relay 132, the relay 138,the run motor sensor switch 110, to the motor 65. Current flowingthrough the resistive element 144 reduces the magnitude of the currentdelivered to the motor 65, thereby reducing the power delivered by themotor 65. Thus, when the cutting instrument 32 is (i) very near to thebeginning of its stroke or (ii) very near to the end of its stroke, thepower delivered by the motor 65 is reduced. Conversely, once the cuttinginstrument 32 moves sufficiently far from its beginning point or end ofstroke point, the control circuit 148 may close the switch 146, therebyshorting the resistive element 144, thereby increasing the current tothe motor 65, thereby increasing the power delivered by the motor.

According to various embodiments, the current control circuit furtherincludes lockout sensor switches 136 a-d collectively defining aninterlock circuit 137 through which current from the relay 132, whende-energized, passes in order for electrical operation of the motor 65to be initiated. Each lockout sensor switch 136 a-d may be configured tomaintain an open (i.e., non-conductive) switch state or a closed (i.e.,conductive) switch state responsive to the presence or absence,respectively, of a corresponding condition. Any of the correspondingconditions, if present when the instrument 10 is fired, may result in anunsatisfactory cutting and stapling operation and/or damage to theinstrument 10. Conditions to which the lockout sensor switches 136 a-dmay respond include, for example, (a) the absence of the staplecartridge 34 in the channel 22, (b) the presence of a spent (e.g.,previously fired) staple cartridge 34 in the channel 22, and (c) an open(or otherwise insufficiently closed) position of the anvil 24 withrespect to the channel 22. Other conditions to which the lockout sensorswitches 136 a-d may respond, such as component wear, may be inferredbased upon an accumulated number of firing operations produced by theinstrument 10. Accordingly, in various embodiments, if any of theseconditions exists, the corresponding lockout sensor switches 136 a-dmaintain an open switch state, thus preventing passage of the currentnecessary to initiate operation of the motor 65. Passage of current bythe lockout sensors 136 a-d is allowed, in various embodiments, onlyafter all of the conditions have been remedied. It will be appreciatedthat the above-described conditions are provided by way of example only,and that additional lockout sensor switches for responding to otherconditions detrimental to operation of the instrument 10 may beprovided. It will similarly be appreciated that for embodiments in whichone or more of the above-described conditions may not exist or are of noconcern, the number of lockout sensor switches may be fewer than thatdepicted.

As shown in FIG. 15, the lockout sensor switch 136 a may be implementedusing a normally open switch configuration such that a closed switchstate is maintained when the staple cartridge 34 is in a positioncorresponding to its proper receipt by the channel 22. When the staplecartridge 34 is not installed in the channel 22, or is installedimproperly (e.g., mis-aligned), the lockout sensor switch 136 amaintains an open switch state. Lockout sensor switch 136 b may beimplemented using a normally open switch configuration such that aclosed switch state is maintained only when an unspent staple cartridge34 (i.e., a staple cartridge 34 having a sled 33 in the unfiredposition) is present in the channel 22. The presence of a spent staplecartridge 34 in the channel 22 causes the lockout sensor switch 136 b tomaintain an open switch state. Lockout sensor switch 136 c may beimplemented using a normally open switch configuration such that aclosed switch state is maintained when the anvil 24 is in a closedposition with respect to the channel 22. The lockout sensor switch 136 cmay be controlled in accordance with a time delay feature wherein aclosed switch state is maintained only after the anvil 24 is in theclosed position for a pre-determined period of time.

Lockout sensor switch 136 d may be implemented using a normally closedswitch configuration such that a closed switch state is maintained onlywhen an accumulated number of firings produced by the instrument 10 isless than a pre-determined number. The lockout sensor switch 136 d maybe in communication with a counter 139 configured for maintaining acount representative of the accumulated number of firing operationsperformed by the instrument 10, comparing the count to thepre-determined number, and controlling the switch state of the lockoutsensor switch 136 d based upon the comparison. Although shown separatelyin FIG. 15, it will be appreciated that counter 139 may be integral withthe lockout sensor switch 136 d so as to form a common device.Preferably, the counter 139 is implemented as an electronic devicehaving an input for incrementing the maintained count based upon thetransition of a discrete electrical signal provided thereto. It will beappreciated that a mechanical counter configured for maintaining thecount based upon a mechanical input (e.g., retraction of the firingtrigger 20) may be used instead. When implemented as an electronicdevice, any discrete signal present in the electrical circuit thattransitions once for each firing operation may be utilized for thecounter 139 input. As shown in FIG. 15, for example, the discreteelectrical signal resulting from actuation of the end-of-stroke sensor130 may be utilized. The counter 139 may control the switch state oflockout sensor switch 136 d such that a closed switch state ismaintained when the maintained count is less than a pre-determinednumber stored within the counter 139. When the maintained count is equalto the pre-determined number, the counter 139 causes the lockout sensorswitch 136 d to maintain an open switch state, thus preventing thepassage of current therethrough. It will be appreciated that thepre-determined number stored by the counter 139 may be selectivelyadjusted as required. According to various embodiments, the counter 304may be in communication with an external display (not shown), such as anLCD display, integral to the instrument 10 for indicating to a usereither the maintained count or the difference between the pre-determinednumber and the maintained count.

According to various embodiments, the interlock circuit 137 may compriseone or more indicators visible to the user of the instrument 10 fordisplaying a status of at least one of the lockout sensor switches 136a-d. More details regarding such indicators may be found in publishedU.S. Patent Application Publication No. 2007/0175956, entitled“Electronic Lockouts and Surgical Instrument Including Same,” which isincorporated herein by reference in its entirety. This application alsoincludes example mounting arrangements and configurations for thelockout sensor switches 136 a-d.

In the illustrated embodiment, when the lockout sensor switches 136 a-dcollectively maintain a closed switch state, a single pole, single throwrelay 138 is energized. When the relay 138 is energized, current flowsthrough the relay 138, through the run motor switch sensor 110, and tothe motor 65 via a double pole, double throw relay 140, thereby poweringthe motor 65, allowing it to rotate in the forward direction. Accordingto various embodiments, because the output of the relay 138, onceenergized, maintains the relay 138 in an energized state until relay 132is energized, the interlock circuit 137 will not function to preventoperation of the motor 165 once initiated, even if one or more of theinterlock sensor switches 136 a-d subsequently maintains an open switchstate. In other embodiments, however, it may be necessary or otherwisedesirable to connect the interlock circuit 137 and the relay 138 suchthat one or more the lockout sensor switches 136 a-d must maintain aclosed switch state in order to sustain operation of the motor 165 onceinitiated.

Rotation of the motor in the forward direction causes the ring to movedistally and thereby de-actuate the stop motor sensor switch 142 invarious embodiments. Because the switch 142 is normally closed, asolenoid 141 connected to the switch 142 may be energized. The solenoid141 may be a conventional push-type solenoid that, when energized,causes a plunger (not shown) to be axially extended. Extension of theplunger may operate to retain the closure trigger 18 in the retractedposition, thus preventing the anvil 24 from opening while a firingoperation is in progress (i.e., while the switch 142 is not actuated).Upon de-energization of the solenoid 141, the plunger is retracted suchthat manual release of the closure trigger 18 is possible.

When the actuation member portion reaches the distal most end of itsstroke, the reverse motor switch 130 will be activated, thereby closingthe switch 130 and energizing the relay 132. This causes the relay 132to assume its energized state (not shown in FIG. 11), which causescurrent to bypass the interlock circuit 137 and run motor sensor switch110, and instead causes current to flow to both the normally-closeddouble pole, double throw relay 140 and back to the motor 65, but in amanner, via the relay 140, that causes the motor 65 to reverse itsrotational direction. Because the stop motor sensor switch 142 isnormally closed, current will flow back to the relay 132 to keep itenergized until the switch 142 opens. When the knife 32 is fullyretracted, the stop motor sensor switch 142 is activated, causing theswitch 142 to open, thereby removing power from the motor 65, andde-energizing the solenoid 141.

In the embodiment depicted in FIG. 15, a normally closed retractionswitch 137 is employed which interfaces with refraction trigger 121 (notshown in FIG. 15). When retraction switch 137 is activated, it opens tostop the flow of current to the motor 65. In alternative embodiments(FIG. 15A), the normally closed retraction switch 137 could be replacedwith a variable resistor 137′ that interfaces with retraction trigger121. In such embodiment, when the retraction trigger 121 is notdepressed, the resistance of the variable resistor is minimal to allowmaximum current to flow to the motor 65. When depressed the resistanceincreases in proportion to the depressing force to reduce current to themotor. Such variable resistor may also be replaced with the retractionswitch 131 as described above (see FIG. 15B).

Accidental actuation prevention for a powered endocutter: With theintroduction of powered systems that no longer limit the device functionto the force capabilities of the user, inadvertent initiation of thefiring cycle may become a much more prevalent issue. It will beincreasing ease to “bump” the activation control and have the instrumentbegin firing thereby tripping the lockout of the cartridge or even“jamming” it on tissue, as the user is unaware it has already begunfiring. To eliminate this issue secondary unlock activator switches orbuttons could be used to unlock the firing mechanism. Various lockoutarrangements are disclosed in U.S. Pat. No. 7,644,848, entitled“Electronic Lockouts and Surgical Instrument Including Same” to Swayzeet al., the disclosure of which is herein incorporated by reference inits entirety. This is much the same as the two switch systems used inthe power saw industry as well as the military to protect againstaccidental actuation. The secondary switch can either release the lockon the firing trigger or merely energize the power to the control.

As mentioned above, in using a two-stroke motorized instrument, theoperator first pulls back and locks the closure trigger 18. FIGS. 16 and17 show one embodiment of a way to lock the closure trigger 18 to thepistol grip portion 26 of the handle 6. In the illustrated embodiment,the pistol grip portion 26 includes a hook 150 that is biased to rotateCCW about a pivot point 151 by a torsion spring 152. Also, the closuretrigger 18 includes a closure bar 154. As the operator draws in theclosure trigger 18, the closure bar 154 engages a sloped portion 156 ofthe hook 150, thereby rotating the hook 150 upward (or CW in FIGS. 16and 17) until the closure bar 154 completely passes the sloped portion156 passes into a recessed notch 158 of the hook 150, which locks theclosure trigger 18 in place. The operator may release the closuretrigger 18 by pushing down on a slide button release 160 on the back oropposite side of the pistol grip portion 26. Pushing down the slidebutton release 160 rotates the hook 150 CW such that the closure bar 154is released from the recessed notch 158. Other arrangements forreleasably locking the closure trigger 18 are disclosed in U.S. Pat. No.7,422,139 which has been herein incorporated by reference.

As can be seen in FIGS. 16 and 17, in various embodiments, a closurelock switch 151 may be mounted in the hook 150 such that that isactivated only when the hook 150 is latched in place. However, theclosure lock switch 151 may be mounted in the pistol grip portion 26 foractivation by the closure trigger 18 when the closure trigger 18 islocked in position. In still other alternative embodiments, the closurelock switch 151 is mounted to the end effector such that it is activatedonly when the anvil or other movable portion is in the “closed”position. Regardless of the specific location of the closure lock switch151, in various embodiments, the closure lock switch is a normally openswitch that will be closed upon locking of the closure trigger 18 orotherwise manipulating the end effector to a “closed” position.

FIG. 18 is a schematic diagram of an electrical circuit of theinstrument 10 according to various embodiments of the present inventionillustrating the use of the closure lock switch 151. As can be seen inthat Figure, current will not be permitted to flow from the battery 64to the motor 65 even if a cartridge is present unless the closure lockswitch 151 is closed. Thus, the motor 65 cannot be operated unless theclosure trigger is in the locked closed position which also reflectsthat the end effector is in the closed state.

Various embodiments may further include a start switch 153 that must beactivated by the surgeon before current will be permitted to flow fromthe battery 64 to the other circuit components and ultimately to themotor 65. Start switch 153 is normally open and may be located at aconvenient location on the handle 6. See FIG. 1. Thus, in theseembodiments, even if the end effector contains a cartridge and theclosure trigger 18 is locked in a closed position, current will not bepermitted to flow to the motor 65 until the start switch 153 is closedby the surgeon. In alternative embodiments, the start switch 153 maycomprise a mechanical switch that prevents the firing trigger 20 frombeing physically rotated toward the pistol grip portion unless theswitch 153 is moved to an actuated position.

Active adjustable staple height for a powered endocutter: Staple heightthat is adjustable to the tissue thickness and type has been pursued formany years. Most recently, U.S. patent application Ser. No. 11/231,456,filed Sep. 21, 2005, now U.S. Pat. No. 7,407,078 and U.S. patentapplication Ser. No. 11/540,735, filed Sep. 29, 2006, now U.S. Pat. No.7,467,740, the disclosures of which are each hereby incorporated byreference in their respective entireties generally involve a flexiblecoupling member or supports that would allow the gap of the instrumentto enlarge with loads induced by thicker tissue in the device. This“passive” variable staple height allows the thickness of the tissue tocreate larger staple forms.

With the introduction of a power source within the instrument thisallows for the use of electricity to change the height of an internalelement within the dynamic coupling element with would change the heightof the staple “actively” by the surgeon or instrument setting thedesired height. This internal element could be a shape memory materialand the electricity changes its temperature and therefore allows it tochange its physical height due to preset configuration. Another viablemethod would be the inclusion of an electro-active polymer (EAP) thatthrough the introduction of an electric field allows it to change itsheight and width. Yet a third embodiment would be to utilize atraditional linear electrical stepper element that can ratchet a smalladjustable screw element within the coupling beam that would adjust itsheight.

More specifically and with reference to FIGS. 19 and 20, an end effector12 of various embodiments of the present invention is shown incross-section with the anvil 24 in a closed or clamped position. As canbe seen, the cutting instrument or knife 32 has a lower actuator portion37 that has a threaded sleeve or nut portion 37′ that is configured tothreadably engage the helical screw shaft 36. In addition, a fin 39protrudes laterally from each lateral side of the nut portion 37 toconfront corresponding slide portions 23 of the channel 22. As can alsobe seen in FIG. 19, the knife 32 has an upper actuator portion 41 thatis sized to be received within a longitudinal T-shaped slot 43 in theanvil 24. As can be seen in FIG. 19, a pair of upper retainer pins 41′protrude laterally from each side of the upper actuator portion 41 ofthe knife 32. Each upper retainer pin 41′ is configured to extend into acorresponding portion of the T-shaped slot 43 provided in the anvil 24.Thus, as the knife 32 is driven distally through the end effector 12,the fins 39 and the retainer pins 41′ serve to limit the amount of spacebetween the anvil 24 and the cartridge 34 to a maximum amount ofpredetermined space.

Various embodiments of the present invention are provided with means foradjusting the amount of space between the anvil 24 and the cartridge 34installed within the channel 22. For example, in some embodiments, eachfin 39 supports a sled contact 45 for sliding contact with correspondingelectrical contacts 47 that are mounted within each slide portion 23 ofthe channel 22. The electrical contacts 47 are elongated and extendwithin the channel 22 so that the sled contacts 45 are always on contactwith their corresponding electrical contact 47 as the knife 32 is drivenwithin the channel 22. Electrical contacts 47 are connected to the powersource or battery 64 and are configured to receive current therefromwhen the motor 65 is powered to drive the knife 32 distally. Also incertain embodiments, an electrically responsive height adjustment member49 is mounted to each retainer pin 41′ as shown in FIG. 19. The heightadjustment members 49 are electrically coupled to the sled contacts 45to receive electrical current therefrom. In various embodiments, theheight adjustment members 49 may comprise shape memory material that,when electrified, changes its physical height due to a presetconfiguration. Thus, depending upon the amount of current received, theheight adjust member members 49 may expand and force the anvil 24towards the cartridge 34 to thereby reduce the amount of spacetherebetween. The amount that such material is proportional to theamount of current received and is known. A control circuit (not shown)may be employed to control the amount of expansion and hence the amountof space between the anvil 24 and the cartridge 34. In otherembodiments, the height adjustment material comprises an electro-activepolymer (EAP) that is retained within a pocket in the pin 41 or isotherwise attached thereto.

FIG. 21 illustrates another embodiment that is similar to the embodimentdepicted in FIG. 19. However, in this embodiment, the height adjustmentmembers 49 are mounted in the anvil 24 and receive current from thepower source through conductors attached directly thereto. Thus, in thisembodiment, the contacts 43 and 45 as described above are not needed.

FIG. 22 illustrates an alternative knife assembly 32′ that issubstantially identical to the knife assembly 32 described above, exceptthat the retainer pins 41′ are mounted to a separate upper actuatorportion 302 that is selectively movable in a vertical direction “VD”relative to a lower portion 300 of the knife assembly 32′. A secondmotor 304 may be mounted to the lower portion 300 and have a lead screw306 that threadably engages a nut portion 308 of the upper retainerportion 302. The upper retainer portion has a “T”-shaped tongue portion310 that slidably extends into a correspondingly shaped slot 312 in thelower portion 300 to prevent rotation of the upper retainer portion 302relative to the lower retainer portion 300 while permitting the upperretainer portion 302 to move vertically relative thereto. Thus, thedistance between the upper and lower retainer portions 302, 300 may beadjusted by powering the second motor 304. Accordingly, if the surgeonwants to reduce the amount of space between the anvil 24 and thecartridge 34, second motor 304 is powered to rotate in a first directionto draw the upper retainer portion 302 towards the lower retainerportion 300. If however, the surgeon desires to increase the amount ofspace between the anvil 24 and the cartridge 34, the second motor 304 isrotated in an opposite direction.

Various embodiments of the present invention include end-effectorillumination methods and methods for illuminating the surgical site whenemploying a powered endocutter. Currently when the end-effector is in ornear its deployment position it is sometimes difficult for the surgeonto visualize the treatment site as there are shadows cast by adjacentstructures as well as the end-effector may even be behind anotherstructure entirely. FIG. 23 illustrates in general form, a distal end402 of a surgical stapler 400 of various embodiments of the presentinvention which includes an anvil 404, a cartridge body 406, and channel408. As seen from that Figure, an additional light source 410 may bepositioned on the end of the cartridge body 406 to illuminate tissue401. This light source 410 could be any combination of practical meansthat convert electrical energy to light including but not limited tosemiconductor (such as LED), a conventional incandescent or filamentbulb, electroluminescent or laser that may be powered from a batterysupported in the instrument handle or in other embodiments, powered byalternating current. Such arrangements would allow the surgeon to notonly light up the treatment site directly, they could allow forbacklighting of structures to see the internal components likevasculature and facilitate the use of a laser pointer through atraditional scope to point out areas of interest to others.

In various embodiments, one or more contacts 420 are provided on theback of the cartridge body 406 that are configured to engage contacts422 within the channel 408. See FIG. 24. This would allow the surgeon toenergize the light 410 as needed by energizing contact set via a switchpositioned on the handle 430. This switch could even have variableintensity as the one described in could control the actuation speed ofthe main, device. Other lighting arrangements for lighting the end of ananvil attached to a circular surgical stapler are disclosed in U.S.Patent Application Publication No. US 2010/0096435 A1, entitled“Surgical Stapling Instrument With Apparatus For Providing AnvilPosition Feedback”, Published Apr. 22, 2010, the entire disclosure ofwhich is hereby incorporated by reference.

U.S. Patent Application Publication No. 2007/0175949 A1, entitled“Surgical Instrument Having a Feedback System”, Published Aug. 2, 2007,the entire disclosure of which is hereby incorporated by reference,further discloses in FIGS. 45-47 of that Publication output displaysthat could show among other this position feedback of the end-effector,lockout status, number of firings etc. This would minimize one of themore difficult issues for the user, which is the identification of thestatus of a device, especially the lockout status of the device withoutactuating the device. An additional feedback that would be helpful forthe user would be immediate feedback as to the status of the cartridgewhen it is loaded. As in the above application it could be rolled upinto the lockout indication on the handle 430. An indicator 432 (such asan LED, glass bulb, LCD, sonic enunciator, vibrator, etc.) could solelybe associated with the status of a cartridge lockout means or mechanismsuch that it providing this information to the surgeon. This LED couldbe located on the handle 430. See FIG. 26. Alternatively an indicator434 could be located near the distal end 402 which would provideimmediate information to the surgeon and loader if the cartridge is“good to go” or not. See FIG. 25. This can be accomplished with a switchor set of contacts associated directly with the mechanical lockout. Theswitch or contacts complete a circuit such that the indicator providesappropriate information. This completed contact set could be through aconductive element within the sled (part 33 in U.S. Patent ApplicationPublication No. US 2007/0175958) and the two contacts could be in theproximal position of the channel (part 22). Another way to detectlockout status is indirectly through instrument status (example I:loaded cartridge and no attempt to fire would indicate lockout is notengaged; example 2: fired instrument and no new cartridge installedwould indicate lockout is engaged; etc.). Another embodiment would be toplace the LED or visual indication cue on the cartridge itself. When thecartridge is snapped into place it creates a contact that supplies thecartridge with power. Should the cartridge be fired not only does themechanical lockout stop the advancement of the knife the cartridgecircuit light up the LED on the cartridge informing the surgeon on thescope monitor that the cartridge is locked out. This could be furtherexpanded by placing a small battery or other charge accumulator withinthe cartridge itself to eliminate the need for a power connection to themain device. Also the cartridge circuit could be set to light thelockout light whenever the device is closed to inform the user there isa spent cartridge in the device.

Indication feedback for powered articulation and cartridge color:Indicating the type of cartridge installed (color) and angle ofarticulation is considered useful to the surgeon. The indication ofarticulation angle could be indicated in several ways includingnumerically or graphically as in an arc of LEDs. The location of thisindication could be on the handle in a convenient location or on theshaft of the device just proximal to the end-effector. The end-effectorfeedback could be passive or active. The active would light upadditional LEDs to show the angle. The passive could just show a halfpie lighted up so the surgeon could intuit how articulated theend-effector is. As we further explore the surgical procedures itbecomes more and more obvious that the surgeon's eyes need to be on thesurgical site not on the handle of the instrument. We also begin tounderstand the surgeon's need for complete status feedback from thedevice. Articulation angle could be illuminated as part of thearticulation joint itself. With lights, LEDs, etc. denoting thediffering angle or even a small LCD denoting angle in degrees. Thiswould allow the surgeon to have some feedback on the angle off ofstraight so he/she can easily navigate back to this angle after removaland reinsertion. Another issue is “obvious” indication of what colorcartridge is in the device. This can be accomplished by a color codedlight array on either the end-effector or the cartridge. Thisinformation could also be transmitted back to the handle to display a“redundant” display to assure there is minimal confusion as to whatcartridge is in the jaws. Another improvement could include a small leafspring contact connected to the proximal deck of the cartridge thatindicates if a minimum tissue pressure has been achieved within thejaws. This minimum pressure would at the very least indicate if a thicktissue cartridge is being used in thin tissue applications, as it wouldnot light if insufficient tissue pressure on the deck were present.

There is a possible need of a method for the introduction of non-sterilebattery packs (possibly with the electronics integral to the batterypack if programmable logic becomes a key customer need). A patentalready exists within the orthopedic drill industry for the insertion ofa non-sterile battery pack within a separately sterilized re-useabledevice. This innovation is intended to improve that concept by utilizingthe disposable device sterile packaging to protect the sterility of theinstrument during the insertion of the non-sterile battery pack. Afurther improvement would be the inclusion of a “hatch” door designedwithin the instrument and closable after the pack has been inserted butbefore the device is removed from the final sterile packaging. Thishatch would then “contain” the non-sterile battery that couldcontaminate the sterile surgical field. The method here would be toinclude an additional layer of packaging that would have a perforatedarea that the battery could be pushed through, either rupturing theextra layer and allowing the battery through or going with the electrodeset of the battery only to be ruptured by the exposable pin tips of thebattery at complete insertion. An alternative of this would be to havethe internal terminals of the gun (deep inside the battery protectioncavity) rupture the sterile barrier and seat within pinholes in thebattery pack. The hatch could then be closed through the sterile packsealing the system. The gun could then be handed into the sterile fieldnormally as any sterile device could.

Position Locator Embodiments I Linear encoder and load control of motorparameters: U.S. Pat. Nos. 6,646,307 and 6,716,223 disclose themechanisms for the measurement of rotation and related torque to controlmotor parameters and optimizing of those parameters based onidentification of end-effector configurations and loading. U.S. PatentApplication Publication No. 2007/0175958 shows a method through the useof a threaded length of the primary shaft in FIGS. 8-13 how this type oflinear motion control could be used to control the trigger location. Thesame type of method could be used for electronic linear control methods.The end-effector could identify its length and type mechanically bydepressing at least one spring biased plunger, which could identify tothe handle the type, and length it would allow the motor to run. Themotor rotation could be converted from rotary motion to linear rack orcable motion, which could then be used to adjust motor voltage, current,and speed to affect the desired linear motion of the control slide. Thecontrol slide could then be directly coupled to the knife drive motion.This control slide could have discrete or continuous “stop” locationsthat the plunger identifier marks as the max “go to” linear displacementbefore retraction

Identification of modular reloads with linear drive: A useful featurefor a surgical instrument is the ability to identify which end-effectorhas been attached to the instrument. In the case of a powered surgicalstapler, several different types of end-effectors could be attached.Additionally, a type of end-effector may have at least one functionand/or feature that is selectively utilized or enabled. Disclosed aremeans for identifying which end-effector is attached. Note that the“type” of end-effector referenced below is not limited to mechanical,pneumatic or hydraulically coupled end-effectors. The instrument maytake different actions, adjust operating parameters, indicate availablefunctions etc. as a result of detecting this end effector.

The end-effector has an electrical connection that is made when it isattached to the instrument. The instrument communicates with theend-effector and reads at least one of several types of signals. Aswitch position or contact position indicates which type of end-effectoris present. A passive element is measured for impedance and the resultindicates which type of end-effector is present.

The end-effector has a radio frequency link to the instrument and datais transferred in at least one direction between the end-effector andthe instrument.

The end-effector has an acoustic link to the instrument and data istransferred in at least one direction between the end-effector and theinstrument.

The end-effector has an optical link to the instrument and data istransferred in at least one direction between the end-effector and theinstrument.

The end-effector has mechanical link that engages elements (such asswitches or contacts) in the instrument that identify it and therebydata is transferred in at least one direction between the end-effectorand the instrument.

While the present invention has been illustrated by description ofseveral embodiments and while the illustrative embodiments have beendescribed in considerable detail, it is not the intention of theapplicant to restrict or in any way limit the scope of the appendedclaims to such detail. Additional advantages and modifications mayreadily appear to those skilled in the art.

For example, although the embodiments described above have advantagesfor an endoscopically employed surgical severing and stapling instrument10, a similar embodiments may be used in other clinical procedures. Itis generally accepted that endoscopic procedures are more common thanlaparoscopic procedures. Accordingly, the present invention has beendiscussed in terms of endoscopic procedures and apparatus. However, useherein of terms such as “endoscopic”, should not be construed to limitthe present invention to a surgical instrument for use only inconjunction with an endoscopic tube (i.e., trocar). On the contrary, itis believed that the present invention may find use in any procedurewhere access is limited to a small incision, including but not limitedto laparoscopic procedures, as well as open procedures.

Any patent, publication, or information, in whole or in part, that issaid to be incorporated by reference herein is incorporated herein onlyto the extent that the incorporated material does not conflict withexisting definitions, statements, or other disclosure material set forthin this document. As such the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.

While this invention has been described as having exemplary designs, thepresent invention may be further modified within the spirit and scope ofthe disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

What is claimed is:
 1. A surgical fastener apparatus comprising: an end effector comprising first and second jaws selectively movable between open and closed positions, said first jaw operably supporting a plurality of surgical fasteners therein; an actuator member supported for selective advancement through said end effector when said first and second jaws are in said closed position such that as said actuator is advanced therethrough in a first direction, said surgical fasteners are driven out of said first jaw into forming contact with said second jaw; an electrically powered motor operably interfacing with the actuator member to apply deployment and retraction motions thereto; a firing actuator operably interfacing with said electrically-powered motor, said firing actuator including an activated position wherein said motor applies said deployment motion to the actuator member; and an electrically activated reversing mechanism for moving said actuator member from a distal most position within said end effector to a proximal position, such that actuation of the electrically activated reversing mechanism causes said firing actuator to be deactivated, and wherein after actuation of said electrically activated reversing mechanism, proximal movement of said actuator member can be stopped by returning said firing actuator to its activated position.
 2. The surgical fastener apparatus of claim 1 wherein said motor is controlled by a motor control circuit comprising a run motor control switch connected to a power source and operated by said firing actuator such that when said firing actuator is moved to said activated position, said run motor control switch permits current to flow to said motor in a first direction to cause said motor to distally deploy said actuator member into said end effector and wherein said electrically activated reversing mechanism comprises a reverse motor switch in said motor control circuit for causing said current to flow in a second direction to said motor to cause said motor to retract said actuator member in a proximal direction when said actuator member reaches said distal most position within said end effector.
 3. The surgical fastener apparatus of claim 2 wherein said motor control circuit further comprises a stop motor switch that stops said flow of current in said second direction when said actuator member is moved to a proximal most position.
 4. The surgical fastener apparatus of claim 2 wherein said reversing mechanism further comprises a retraction switch in said motor control circuit, said refraction switch operated by a retraction actuator such that upon activation of said retraction actuator, said retraction switch stops said flow of current in said second direction to said motor.
 5. The surgical fastener apparatus of claim 4 wherein said retraction switch comprises a variable resistor.
 6. The surgical fastener apparatus of claim 5 wherein said retraction switch further comprises a normally closed contact portion.
 7. The surgical fastener apparatus of claim 4 wherein said retraction actuator is biased into an unactuated position by a biasing member.
 8. A surgical fastener apparatus comprising: an end effector; an actuator supported relative to said end effector and being selectively movable between an unactuated position to actuated positions within said end effector; an electric motor operably interfacing with said actuator to selectively apply a distal driving motion thereto to move said actuator from said unactuated position to said actuated positions and to selectively apply a proximal driving motion to said actuator to retract said actuator to said unactuated position from said actuated positions; a firing actuator; a motor control circuit for controlling the motor, said motor control circuit comprising: a power source connected to said motor for electrically powering the motor; and a current control circuit connected to the power source for controlling current supplied to said motor from said power source, said current control circuit comprising: a run motor control switch connected to said power source and operated by said actuator such that upon application of said actuation motion to said firing actuator, said run motor switch permits current to flow to said motor in a first direction to cause said motor to apply said distal driving motion to said actuator; and a reverse motor switch connected to said power source such that when said actuator has moved to a distal most actuated position, said reverse motor switch permits current to flow to said motor in a second direction to cause said motor to apply said proximal driving motion to said actuator, said current control circuit further configured to alter said application of said proximal driving motion upon receipt of an application of a retraction motion thereto.
 9. The surgical apparatus of claim 10 further comprising a retraction actuator and wherein said current control circuit comprises a retraction switch connected to said power source and operated by said retraction actuator such that upon application of said retraction motion to said retraction actuator, said retraction switch alters said flow of current in said second direction to said motor.
 10. The surgical apparatus of claim 11 wherein retraction switch comprises a variable resistor.
 11. The surgical apparatus of claim 10 wherein said retraction switch further comprises a normally closed contact portion.
 12. The surgical fastener apparatus of claim 9 wherein said retraction trigger is biased into an unactuated position by a biasing member.
 13. The surgical fastener apparatus of claim 9 wherein upon application of said retraction motion to said retraction actuator, said retraction switch stops said flow of current in said second direction to said motor. 